NOV 03, 2011
This study published in the October issue of the British Journal of Ophthalmology reports on a prospective clinical series of 11 patients who underwent unilateral keratopigmentation (KTP) for moderate to severe visual function disabilities due to iris defects and pupil abnormalities. After 12 months of follow-up, all patients experienced significant improvement, including total elimination of visual-function related symptoms in some cases. The authors conclude that KTP using new micronized mineral pigments and new surgical protocols appears to be effective for the management of moderate to severe visual dysfunction related to iris defects, and provides adequate cosmetic and functional outcomes with less invasiveness than other procedures.
Eleven eyes were treated with KTP for functional and cosmetic restoration using original micronized mineral pigments and new KTP techniques, including manual intralamellar keratopigmentation (MIK), femtosecond assisted keratopigmentation (FAK) and superficial automated keratopigmentation (SAK). The cases included traumatic aniridia, large iris defects and colobomas, iridodialysis, iris atrophies, symptomatic peripheral iridectomy and congenital or evolutive iris defects. In all cases, other conservative measures, including cosmetic contact lenses, were previously tried without success.
Eight patients were asymptomatic after the surgery, while minimal nondisabling symptoms remained in two patients. One patient with traumatic aniridia complained of significant residual glare at the three-month postoperative visit and underwent a repeat procedure to reduce the simulated pupil to 4 mm. The cosmetic outcomes were classified as excellent in eight patients and good in three.
The authors believe this to be the first systematic, interventional, consecutive study using KTP as a surgical tool for the management of functional visual problems related to iris defects. They say that other intraocular alternatives for the correction of iris defects have intraoperative or postoperative complications, whereas KTP is minimally invasive and results in a significant decrease in subjective glare, photophobia and monocular diplopia.
They add that use of new micronized mineral pigments that have been studied for tolerance and toxicity presents an additional advantage over other natural pigments because their particle size is reduced by micronizing procedures. The small particle size diminishes the chance of developing a foreign-body reaction against the pigment intruding into the corneal stroma. The new KTP technique using femtosecond technology allows surgeons to customize treatment, which the authors say results in precise and uniform KTP thickness. They add that SAK may provide surgeons with a better way of controlling color and cosmetic appearance, while MIK appears effective for partial iris defects.